1. Field of the Invention
This invention relates to improvements in an overedge sewing machine and more particularly it relates to an overedge sewing machine which is also capable of forming chain stitches without overedge stitches.
2. Description of the Prior Art
In recent years, for the sewing of clothes in homes, or the so-called home-sewing, overedge stitching has become popular among home sewers for them to show their originality or to improve their works. The following types of overedge sewing machines are frequently used for overedge stitching:
(1) The so-called three thread overedge sewing machine having the combined function of seaming and overedging in one that is simultaneously join together and finishing the raw edges of two pieces of fabric (USA FEDERAL STANDARD 751a STITCH TYPES 504 and 505); and
(2) The two thread overedge sewing machine which has only the function of overedging, not being capable of seaming (USA FEDERAL STANDARD 751a STITCH TYPES 502 and 503).
However, such overedge sewing machines, which form overedge stitches, cannot be used for the sole purpose of seaming or joining together; in such cases, for, a sewing operation it is necessary to also a straight stitch forming machine or a double thread chain stitch forming machine, i.e., at least two sewing machines are required for sewing that includes formation of overedge stitches.
Every home sewer cannot afford to possess such two sewing machines, which probably accounts for the fact that overedge stitching has not become widespread in home sewing.
The applicant (assignee) proposed an arrangement wherein, as in Japanese Utility Model Publication Nos. 33983/1983 and 36397/1983, in another type of overedge sewing machine which makes a "true safety stitch" (four threads) with two separate seams--an ordinary two thread overedge stitch and a double thread chain stitch (USA FEDERAL STANDARD 751a STITCH TYPE 515) a double chain stitch forming mechanism is made switchable to the overedge stitch forming mechanism, thus enabling a single sewing machine to form both the overedge stitches for finishing the raw edges and the double chain stitches for seaming two pieces of fabric.
However, although such seaming two pieces of fabric by double thread chain stitches has become possible, three thread overedge stitching, rather than the overedge stitching by the said two thread overedge sewing machine and four thread overedge sewing machine, is used in joining sleeves and closing sides of clothes such as shirts, blouses etc.
Further, three thread overedge stitching, as compared with two thread or four thread overedge stitching, functionally has many applications, such as narrow/rolled hems ideal for use on thin materials such as Crepe de Chine, Silk etc., blind hem used for hemming on trousers or skirts, and pin tucks used for ornament, and, externally it is beautiful because of stitches formed of three threads. For this reason, three thread overedge stitching has been exclusively used in home sewing.
However, there is no three thread overedge sewing machine available which is capable of seaming two pieces of fabric without overedge stitching.